On 4 Oct 2003 23:27:00 -0700, (George William
Herbert) wrote, in part:
Paul F. Dietz wrote:
George William Herbert wrote:

I think that's not true with a travelling charge;
but nobody has made reliable travelling charge guns.

Has anyone mentioned ram accelerators in this thread?

Andrew Higgins posted in the thread, so I think it's
got to have been part of some included library function
or something.

A railgun, or mass driver, built, say, on a gentle slope leading to
the top of a 20-mile-high artificial mountain wouldn't be as good as a
"space elevator", as it would only allow one to eliminate the *first*
stage of a rocket and replace it with electrical power...

but it wouldn't require exotic materials like carbon nanotubes, I
would think. Still, the square-cube law does mean there would be some
problems, and maybe we could get away with a lower height.

I base 20 miles on the fact that rockets generally remain in vertical
flight up to about 20-25 miles to minimize air resistance losses, but
after 20 miles (where the atmosphere is less than 1/1000 of that at
sea level) air resistance tends to be regarded as unimportant. But I
admit I'm no expert at this, and of course every mile shaved off of
the needed height would greatly reduce the cost of such an artificial
mountain.

John Savard

John Savard
http://home.ecn.ab.ca/~jsavard/index.html